Potato digger with power lift



March 18, 1947. YQUNG 2,417,580

POTATO DIGGER WITH POWER LIFT Origipal Filed Eeb. 10, 1941 3 Sheets-Shet l INVENTOR: Al JSTlN E. YOU

--March 18', 1947. A. E. YOUNG 2,417,580

POTATO DIGGER WITH POWER LIFT Original Filed Feb. '10, 1941 3 Sheets-Sh9et 2 ATTORNEYS.

-FIG.6

March 18, 1947. YOUNG 2,417,580

.POTATO DIGGER WITH POWER LIFT Original Filed Feb. 10, 1941- 3 sheets Sheet 3 INVENTOR:

, AUSTIN E. YOUNG l/i/i A TTORNEYS.

Patented Mar. 18, 1947 2,417,580 Po'rA'ro moose wrrn POWER LIFT Austin E. Young, Syracuse, N. i Y., assignor to Syracuse Chilled Plow 00., Inc., Syracuse, N. Y., a corporation of New York Continuation of application Serial No. 378,122, February 10, 1941. This application filed March 15, 1944, Serial No. 526,828

This application is a continuation of my copending application, Serial N 0. 378,122, filed February 10, 1941, fcr'Potato diggers, and contains subject matter similar to that disclosed in my copending application Serial No. 524,940, filed March 3, 1944,

The present invention relates generally to ag icultural implements, such as potato diggers and the like, and is more particularly concerned with lifting clutch mechanism for raising and lowering the operating means'between ground engaging and transport positions.

The object and general nature of the present invention is the provision of power lift clutch mechanism for a, potato digger or the like, which mechanism is driven from the power means for driving the elevator chain or chains of the implement. Another important feature of the present invention resides in the provision of a tworow potato digger, each having a movable shovel unit, both of which are raisedand lowered by a power lift clutch mechanism on one of the implements. Further, it is a feature of this invention to provide lifting connections with the shovel units whereby either may be adjusted in operat ing position independently of the other, yet both raised to transport position whenever the power lift clutch is actuated.

An additional feature of the present invention is the provision of improved self-interrupting clutch mechanism in which two driven parts are connected through planetary gear units with a continuously rotatable driving part, and in which a suitable control is arranged normally to hold one of the driven par-ts against rotation but movable into a position to lock the other against rotation to drive the first mentioned driven part. In this connection, it is another feature of this invention to provide means for automatically restoring the control means to a position in which the operative driven part is locked in non-rotating position.

These and other objects and advantages of the present invention will be apparent to those skilled in the art after a consideration of the following detailed description, taken in conjunction with the accompanying drawings.

In the drawings: 1

Figure 1 is a plan View of a two-row digger in which the principles of the present invention have been incorporated;

Figure 2 is an inner side view taken along the position in dotted lines;

2'7 Claims.

Figure 3 is a sectional view, taken generally along the line 3--3 of Figure 1, showing the man ually controlled depth adjusting means;

Figure 4 is a detail view of the connection between the raising link and the rock shaft which is connected with the shovel unit;

Figure 5 is a side view of the power actuated self-interrupting clutch mechanism shown in Figure l as connected to raise and lower the shovel units of both implements, parts being broken away to show the interior construction;

Figure 6 is a sectional View taken along the line li6 of Figure 5;

Figure 7 is a fragmentary side view, showing the trip lever in its operating position for raising orlowering the shovels; and

Figure 8 is a fragmentary View showing the means for limiting the outward movement of the clutch control trip lever.

Referring now more particularly to Figure 1, it will be noted that the two-row potato digger shown in this figure comprises two substantially complete implements, the left-hand implement being indicated by the reference numeral l and the right-hand implement by the reference numeral 2. 7 Each implement includes a. frame 4, the frame bars 5 and 6 of which converge forwardly and are connected by a bracket 1 to the transverse axle 8 of a front truck 9, and may be adjusted laterally, as by bolting the brackets i .in different holes la in the axle 8. The front able brackets (Figure 2), the axle l6 extending from one side to the other of the two intercom nected implements. A round wheel i3 is carried at each end of the axle l6, and the ground wheels l8, together with the front caster wheels it, support the machine during transport and in operation. Preferably, the brackets I! may be connected to the axle 16 at laterally adjusted points, so that, with the above mentioned lateral adjustment of the brackets I, the two digger units may be adjusted for different row spacings, if desired.

Each of the implements I and 2 is, in general, constructed similar to the potato digger shown in the patent to Curtiss L. Cook, 2,172,435, issued September 12, 1939, to which reference may be made if necessary. Briefly, each of the implements I and 2 comprises, in addition to the parts mentioned above, a tool or shovel unit 20 connected to the forward end of the frame 4, an elevator chain 2| of the usual rod construction, and driving mechanism for the chain, preferably in the form of a transverse shaft 23 supported in bearings 24 on the frame bars and 6, a pair of sprocket members 25 and 2'! about which the elevator chain 2| is trained, and a'driving sprocket 28 fixed to one end of the shaft 23. Each of the implements and 2 also includes other features, such as supporting and agitating sprockets and rear deflectors.

Each shovel unit comprises a frame made up of a pair of angle members35 and 38 to the lower ends of which a pointed shovel 31 is connected in any suitable manner. The rear ends of the two angle members 35 and 35, which serve-as arms supporting the associated shovel 31, are pivotally connected, as at'39; to brackets 40 fixed to the generally central portions of the two frame members 5a and 6a. Each shovel 31 is capable of vertical swinging movement about the axis defined by the pivots 39. Overlapping plates 4| and 42 are fixed, respectively, to the frame and shovel bars, whichwith a pair of curved plates or guard members 43 define the throat of the implement. Preferably, the curved guards 43 are connected to the forward end of the lower plates 42.

Each shovel unit is raised and lowered by means mounted on the forward end'of the associated implement frame. Preferably, such means includes a transverse rock shaft 41 journaled in a pair of brackets 48 and 49 fixed, as by bolts 55, to the associated frame angles 5 and 6. Secured to the inner end of each of the rock shafts 41 is a lifting arm or bell crank 5|, the forwardly extending arm section 52 of which is connected by means of link sections 54a and 541) with the forward end of the shovel arm or angle 35. An arm 53 is fixed to the outer end of the rock shaft 41 and is connected by means'of similar link means 55 to the forward end of the other shovel armor angle 35. Thus, each shovel unit may be raised and lowered by rocking and associated transverse rock shaft 41. Both of the arms 5| and 53 are fixed in any suitable way rigidly to the rock shaft 41 associated therewith.

As best shown in Figure 3, suitable hand-controlled means is provided for limiting the downward movement of the shovel unit of each implement. To this end, a cam-like arm 58 is fixed to each lifting rock shaft 41 adjacent the bracket 48, and pivotally mounted on the shaft 41 is a hand lever 59 having the usual detent mechanism adapted to latch the hand lever 59 to a sector 8| formed on or carried by the bracket 48. The hand lever 59 includes an abutment or stop member 82 with which the outer end of the stop arm 58 is adapted to engage. As will be seen from Figure 3, moving the hand lever 59 to various positions permits the associated shovel unit 31 to move to various lowered or operating positions. If desired, the hand lever 59 maybe used to raise the associated shove] unit into a raised or transport position, but preferably suitable mechanism deriving power from the driving means for the elevator chains is employed for raising both shovel units at the same time, as will be described below.

As mentioned above, power for driving the two elevator chains 2| is derived from the tractor power take-01f shaft l4, and as best shown in Figand a pair of universals 88 and 89 to the power 4 ures 1 and 2, the power drive means is substantially the same as the power drive shown in the co-pending application of Curtiss L. Cook, filed July 18, 1940, Serial No. 346,073. Briefly, the power drive mechanism, indicated in its entirety by the reference numeral 56, comprising power shaft means extending from the shaft l4 rearwardly to a rear power shaft section 7| is connected by suitable gearing, indicated at 12, to a transverse drive shaft 73 supported in bearings carried by a pair of vertically extending brackets 14 and 15. The left or outer end of the jackshaft 13 carries a sprocket 16 around which a driving chain TI is trained, the chain passing around the driving sprocket 28 on the drive shaft 23 of the left-hand digger unit, whereby power is delivered from the tractor motor through the power shaft sections and the transverse power shaft or jackshaft 13 to the elevator chain 2| of the left-hand unit. The right-hand potato digger unit 2 is provided with a power shaft or jackshaft 9| similar to the shaft 73. The jackshaft 8| is supported in a' bracket 82 fixed to the laterally outer side of thepotato digger unit 2 and supported at its laterally inner end in a laterally extending plate 83 fixed to a bracket 84 carried at the laterally inner side of the implement 2. The shaft 8| is connected by telescopic cross shaft sections 81 shaft or jackshaft i3 of the left-hand implement The telescopic cross shaft sections 81 accommodate any lateral adjustment of one implement relative to the other, and they also accommodate relative movement of one digger with respect to the other if the front ends are not supported at the same height, as might occur when the front truck passes over uneven ground. The outer end of the shaft'BI carries a sprocket around which a chain 89 is trained, the chain 89' extending around the driving sprocket 28 of the implement 2. Thus, power from the tractor power take-off shaft 4 is delivered to both of the elevator chains 2| of the two interconnected implements.

According to the principles of the present invention, power is taken from the jackshaft 73 of the left-hand implement to drive a self-interrupting clutch mechanism which is connected to raise both of the shovel units 13 of the two units at the same time. This power lift clutch mechanism and associated parts will now be described. A sprocket is fixed to the jackshaft 73 just inside the universal joint 89 and receives a drive chain 95 which at its lower end is trained around the driving sprocket 91, which forms a part of the self-interrupting clutch mechanism, indicated in its entirety by the reference numeral 98. Thus, the sprocket 9'! is continuously driven from the jackshaft 13 during all times that the outfit is in operation. Referring now more particularly to Figures 5 and 6, a lift support plate |9| is mounted in any suitable manner on the inside frame bar 5a of the left-hand implement and receives a bolt I82 by which a stationary bushing I93 is firmly secured in place. The drive sprocket 97 is journaled for rotation on the bushing Hi3 and is provided with a hub I84 in one end of which gear teeth I55 are formed. The hub I54 thus forms the driving gear of the clutch unit 98. A rotatable housing I58 is mounted on the hub I54 and is provided with a central hub section I57 which at two diametrically opposite points is slotted out, as at I58, to receive the larger gear section I59 of a compound planet gear,

' indicated in its entirety by the reference numeral H9. If desired, I may employ only one gear member II'iI, but two may be used, as shown in Figure 6. Each gear member II is mounted for rotation on a stud I ll fixed to the rotatable housing I06 in any suitable manner, as by being threaded into the radial web portion thereof. A second rotatable housing H is provided with a hub H6 and is rotatably journaled on the Stationary bushing I03. 7 The hub H6 is received within the laterally outer end of the hub I01, whereby all of these parts are maintained in accurate concentric relation. The rotatable housing IIE'is formed peripherally as an internal ring gear, indicated at H9, and is provided with teeth I which mesh with the other gear section .I2i of each of the compound planet gears IIO. Thus, as best shown in Figure 6, the clutch mechanism 98 includes planetary gearing, of which the hub I04 is the driving member and the two rotatable housings I05 and I I5 the driven members, the latter being driven by means of the planetary gears IIO. As will be readily understood, either of the members I03 and H5, if held against rotation, may serve as the reaction member by which the gears IIO will drive the other member. As described above, the hub I04 with the teeth I05 serves as the sun gear, the gears I0 serve as the planet gears of which the member IE3 is the planet gear carrier, and the other rotatable housing I I5 serves as the ring gear.

According to the principles of the present in-' vention, the rotatable housing H5 is link-connected with the two shovel units for the purpose of raising and lowering them, and suitable control means is provided for locking one or the other of the members I06 and I I5 against rotation and releasing the other member topermit it to rotate, whereby a positive driving connection is established through the clutch mechanism, both during the raising and lowering movements of the two interconnected shovel units. I

As will be seen from Figures 1, 2 and 5, the rotatable housing member I03 is provided with a radial flange I23 which is formed with a plurality of peripheral notches or scallops I21. As will also be seen from Figure 6, the radial flange I26 is offset axially so as to lie in a plane closely adjacent a flange I 30 that is formed on the other rotatable housing member H5. The member H5 is provided on the flange I30 with a stop lug or cam I32 and an adjacent trip lug or cam I33. The lugs I32 and I33, and the adjacent portions form notches 34 and I35 in the periphery of the member II5. Cooperating with the notches I21 and-the lugs I32 and I33 is a trip or control lever I35. The lever I36 is mounted for rock ing movement on a stud I 31 fixed in any suitable manner to the supporting plate IOI. It will be noted, particularly from Figure 5, that the lug or lugs I32 do not extend radially outwardly beyond the bottom of the notches I2 The trip lever I30 is of particular construction. At one side of the axis defined by thejournal portion I38 receiving the lug I31 the lever I30 carries a lug I39 which lies in the plane of the flange I33 on the rotatable housing member H5, and at the other side of the axis of the lever I36 is a lug I40 that extends substantially the axial length of the journal section I38 and is in a position to engage any one of the notches I27 formed in the flange I25 of the rotatable housing member I06. A lug I4! is carried by the trip lever 436 and :serves as a stoplimiting the outward movement of the lever (Figures 7 and 8) as will be explained below. The relation between the lugs I39and I40 is such that only one may be engaged with the associated lugs I32 and notches I21 at any one time for after the lug I39 has been moved out of the notch I34 :and clears the lug I32, it then rides along the flange I30, and in this position of the leverI36 the lug I40 thereon clears the notches I21 on the member I06. In effect, therefore, in this position of the lever I36 it is out of operative engagement with both members I06 and H5. Ordinarily, however, either one or the other is driven; and in that respect each may be said to be intermittently operated. A suitable spring I42 is an-- chored at one end, as at M3, to the supporting plate I01 and at the other end is connected with the lever I35, biasing the same for movement into the position shown in Figure 5, in which the lug I39 engages the, lug I32 on the member H5, thereby holding the latter against rotation while the other lug I40 on the lever I36 clears the notches i21, thereby permitting the member I06 to rotate, it being remembered that the part I06 serves as the planet gear carrier for the planetary gearing of which the members I86 and II 5 are parts.

Referring now more particularly to Figure 1, it will be noted that the member H5 carries a crank pin I 58 which receives the rear end of a lifting link I49. The latter extends forwardly and is threaded at its forward end, as at I5I, to receive a socket Washer I52 and an adjusting nut I53. The socket washer I52, as best shown in Figure 4, seats in a socket I555 formed in the arm E54, which forms a part of the bell crank or arm member 5! that is fixed to the laterally inner end of the lifting rock shaft 4'Iof the left implement i. From Figure 2 it will be noted that the link I ill is thus connected with the lifting means for the left-hand shovel 3'! by a one-way connection; that is, rearward movement of the link I49 will rock the member 5| and raise the tools, but forward movement of the link I43 will not lower the shovel, unless permitted to do so by the depth adjusting lever 59. In other words, the latter determines the operating position of the shovel while the power lift mechanism, just described, controls the raising of the shovel, either operating in one or the other direction independently of the other. The shovel of the right-hand unit is connected so as to be raised at the same time that the left-hand shovel is raised, and to this end, as best shown in Figure 1, the left or laterally inner end of the lifting shaft 41 of the right-hand unit is provided with a lifting bell crank 5!, like that described above, and'a lifting link I59 is pivoted at its rear end on a stud I60 carried by a block Iti which is adjustably secured to the lifting link I :49 by a set screw I 52 or the equivalent. The pivot block IBI is secured to the lifting link I39 well toward the rear so that the link I59 is of the requisite length so that any variation in the position of one digger relative to the other, as by the aforesaid lateral adjustment, or otherwise, will have no appreciable effect upon the action of the power lift mechanism on one digger controlling the shovels of both diggers. The forward end of the right-hand lifting link I59 is formed substantially the same as the forward end of the lifting link I 45 and is provided with the same kind of socket washer I52 and,

adjusting nut I53. By virtue of the construction and connection of the lifting links I49 and 159 andassociated parts, whenever the member I I5 is rotated into the position shown in Figure 1,'

a rearward pull is exerted through the links I49 and I59 to raise both shovels of the left and right-hand implements.

The operation of the control of the power lift clutch mechanism 98 is substantially as follows:

The normal transport or raised position of the parts is shown in Figures 1 and 5. In this position, the weight of the two shovel units is transmitted by the arms 52 and 53 to the lifting shafts 41, and from the latter through the two lifting links I49 and I59 to the rotatable member H5. The arrangement of the parts is such that the pivot stud I48 is slightly above the axis of rotation of the member H5, whereby the weight of t e shovels tends to rotate the member H5 in a clockwise direction, as viewed in Figure 5. However, the spring I42holds the control lever I36 in a position in which the lug I39 engages the lug I32 on the rotatable member I I5, thereby locking the latter against rotation. When the lug I33 on the control lever i36 engages the lug I32 on the member IE5, the other lug I40 on the control lever I36 is in a position clearing the notches l2l. Therefore, since the driving sprocket 9'! and associated sun gear I05 are rotated continuously, this rotation is transmitted by the planet gears I I to the planet gear carrier member I66, acting against the locked member H which is stationary. The sprocket gear 61 is normally driven in the direction of the arrow at shown in Figure 5, and. when the member I I5 is locked against rotation, the notched member I06 is driven idly in the same direction.

When it is desired to lower the shovels into their operating position, which is determined by the hand levers 56 and associated abutment or stop members 62, the operator pulls on the cable I65, thereby swinging the control lever I36 to the position shown in Figure 7, in which the lug I39 is moved away from the lug I32 on the member H5 to which the lifting link I49 is connected, at the same time moving the lug I50 into engagement with one of the notches I21 and thereby locking the latter against rotation in either direction. It will be noted that both of the lugs I39 and I40 are rounded, and the relation of the parts is such that by the time the lug I40 engages in one of the notches I21 far enough to prevent the member I96 from rotating, the other lug I39 is in a position permitting the lug I32 to pass the lug I39. Thus, as soon as the lug I40 locks the member I06 against rotation, the drive is then transmitted through the planetary gearing to the member H5, this member rotating in a clockwise direction, as indicated by the arrow 1) in the lower portion of Figure 5. The weight of the digger shovels and associated parts also tend to turn the member H5 in the direction of arrow 12. If the operator retains his hold on the rope I65, holding the lug M0 in engagement with the member I06, the shovels will be lowered no faster than the member H5 is driven. However, if desired, the operator may release the cable I65 a moment after the trip lever I36 has been operated to release the lug I32. The shovels will then move downwardly under the action of gravity and the lug I39 will merely ride along the flange I36. The lowered position of the shovels 31 is determined by the hand levers 59. After the shovels reach their lowered position, the member I66 merely idles and the member II5 remains stationary. Since the weight of the shovels and other parts tends to hold the member H5 in a position with the pin I48 forward, there is no need for a second set of lugs I32, I33 in the type of clutch shown 1 cable I65, which again moves the control lever I36 into the position shown in Figure '7 which moves the lug I40 into one of the notches I21 and locks the member I06 against rotation, whereupon the member II5 will be driven in the direction of arrow b, rotating the stud I48 in a clockwise direction (Figure 2) until it picks up the shovels and begins raising them. The reaction of raising the shovels by the rotation of the member 9'! tends to cause the member I06 to rotate in a counterclockwise direction. However, this is resisted by the engagement of the lug I40 in one of the notches I21. The operator may therefore release his hold on the cable I65, the reaction exerted through the member I06 thus holding the lever 436 in the position shown in Figure '7. In this position, the lug MI bears against the shoulder I44 (Figure 6) on the member I06, thus limiting the clockwise movement of the trip lever I36 under this reaction The continued rotation of the sprocket 91 therefore continues the clockwise rotation (Figures 2 and 5) until the lug I33 comes into engagement with the lug I40, as shown in Figure 7. At this point the continued rotation of the member H5 therefore acts positively to swing the trip lever I36 in a counterclockwise direction, moving the lug I40 out of engagement with the member I06 and swinging the lug I39 into a position to reengage the lug I32, thus positively swinging the trip lever I36 from the position shown in Figure '7 back to the position shown in Figure 5. The parts are so arranged, that by the time this occurs the pivot I48 passes to a point above the axis of rotation of the member I15, defined by the pivot bolt I02, so that the weight of the raised shovels tends to rotate the member H5 in a clockwise direction (Figure 5), thus holding the lug I32 against the lug I39 on the trip lever I36, thereby locking the rotatable member I I5 in its raised position.

Although the clutch mechanism just described finds its greatest usefulness in potato diggers and other agricultural implements, the clutch mechanism of the present invention obviously may have other uses. For example, if the load is such as to tend to rotate the driven member II5 continuously, or at least through a full revolution, rather than only through approximately a half revolution as in the instant construction, and where the driven member II5 carries only one set of lugs I32, I33, the clutch will automatically disengage after a complete revolution. If it should be desired to provide a self-interrupting clutch which positively disengages, say, every degrees, then two sets of lugs I32, I33 would be provided at points diametrically opposite the lugs i32, I33 shown in Figures 2 and 5. As will be apparent, more than two sets of lugs may be employed and they may be spaced about the periphery of the driven member H5 at any desired spacing so as to secure the desired angular rotation before interruption. It is an important feature of a clutch of the type described that the reaction of the transmission of the driving force is utilized for holding the spring biased trip lever in a position engaging the member I06 until the trip lever I36 is actually forced back into a position holding the driven member against further rotation. v It willbe understood that while I have shown the self-interrupting planetary clutch mechanism It will also be seen that the driven member H may have one, two or more pairs of controlling lugs I32 and I33 depending upon the extent of revolution it is desired that the member H5 shall make before its movement is automatically interrupted.

Thus, while I have shown and described above the preferred structure in which the principles of the present invention have been incorporated, it is to be understood that my invention is not to be limited to the particular details shown and described above,.but that, in fact, widely different means may be employed in the practice of the broader aspects of my invention.

What I claim, therefore, and desire to secure by Letters Patent is:

1. A two-row potato digger comprising a pair of digging implements connected in side by side relation, each including a vertically adjustable shovel unit, elevator chain means supported on said shovel unit and the rear portion of the implement, a shaft supported on one of said implements and connected to drive the elevator chain means of both implements, power means for driving said shaft, power lift mechanism on one implement and operatively connected to be driven by said shaft, and connections between said power lift mechanism and each of said sh'ovel units, whereby actuation of said power lift mechanism raises or lowers both shovel units.

2. A two-row potato digger comprising a pair of implements connected together in side by side relation, each including a generally vertically movable shovel unit, separate relatively movable frame means to which the shovel units are respectively connected, a lifting member movable on each frame means and interconnected with the associated shovel unit to move therewith, and a manually adjustable part on each frame means for limiting the movement of said member in one direction, thereby serving to limit the downward movement of the associated shovel unit, lifting mechanism mounted on the frame means of one of said implements and having a one-way connection with the associated lifting member of that implement, whereby operation of said lifting mechanism acts through said lifting member toraise the shovel unit associated therewith and a connection between said lifting mechanism on said one implement and the lifting member of the other implement whereby said lifting mechanism on said one implement controls the raising of both of said shovel units.

3. A two-row potato digger comprising a pair of implements connected together in side by side relation, each implement including a frame, a vertically adjustable shovel unit connected therewith,

nection and extending to the raising and lower.-

ing means of the other implement whereby both shovel units may be raised and loweredby said I power lift mechanism. I

4. In a two-row potato digger, a pair of implements connected to ether in side by side relation, each including a frame, a shovel unit pivotally connected with said frame, a rock shaft mounted on each of said frames and operatively connected with the associated shovel unit to raise the same, relative to the associated frame, an elevator chain means carried on each frame and the associated shovel unit, and means for driving the elevator chain means, a power lift mechanism carried on the frame of one implement, means for driving the same from the chain driving means of that implement, and an adjustable one-way connection between said power lift mechanism and each of said rock shafts, whereby the power lift mechanism on said one implement may be actuated to raise the shovel units of both implements.

5. A two-row potato digger comprising a pair of implements connected together in side by side relation, each including an elevator chain, a movable shovel unit and a rock shaft connected with the associated shovel unit for raising the same, means for driving the elevator chain of each implement including a j'ackshaft mounted for rotation on each implement, means for driving one of said jackshafts, a driving connection between said one jackshaft and the other jackshaft, a power lift unit carried at the inner side of the implement on which said one jackshaft is mounted, means for driving said power lift unit from said one jackshaft and a connection from said power lift mechanism to the laterally inner portion of each rock shaft.

6. A two-row potato digger comprising a pair of implements connected together in side by side relation, each! including an elevator chain, a movable shovel unit and a rock shaft connected with the associated shovel unit for raising the same, means for driving the elevator chain of each implement including a jackshaft mounted for rotation on each implement, means for driving one of said jackshafts, a connection between said jackshafts, a power lift unit carried at the inner side of the implement on which said one jackshaft is mounted, and a connection including a link extending from said power lift mechanism to the rockshaft on the implement on which said power lift mechanism is mounted, and a link connection from said one link to the laterally inner end of therock shaft mounted on the other implement, the position of one link with respect to the other being adjustable.

7. A powerlift attachment for potato diggers and like implements including operating mechanism, a transverse jackshaft for driving said mechanism, tool means adapted to be raised and lowered, and a rockshaft operatively connected with said tool means for raising and lowering the same, said power lift attachment comprising selfinterrupting clutch means including a driving part and a driven part, means for connecting said ldriving part with said jackshaft, an arm adapted mechanism.

8. A power lift attachment for potato diggers and like implements including operating mechanism, a transverse jackshaft for driving said mechanism, tool means adapted to be raised and lowered, and a rock shaft operatively connected with said tool means for raising and lowering the same, said power lift attachment comprising selfinterrupting clutch means including a driving part and a driven part, means for connecting said driving part with said jackshaft, an arm adapted to be connected to said rock shaft, and

connecting means between said arm and the driven part of said self-interrupting clutch mechanism, said self-interrupting clutch mechanism including planetary gearing for transmitting the drive from said driving part to said driven part, a reaction member associated with said planetary gearing, and a control member movable from a position locking said driven part against rotation to a position locking said reaction member against rotation, whereby said driven part may be driven.

9. An agricultural implement comprising a part to be raised and lowered, means for raising and lowering said part comprising a planetary gear unit including a sun gear, a planet gear carrier member and a ring gear member, driving means for driving said sun gear, connections between said part to be lifted and one of said members and includin a crank on one end of said one member and a link connecting said crank with said part to be lifted, said one member tending to be rotated in one direction by the weight of said part when the latter is in a raised position, a support receiving said one member, the latter extending outwardly at the end of said support receiving said crank so as to accommodate rotation of said crank through a full revolution, and a control having one portion engageable with said one member for holding the latter against movement in said one direction and another portion engageable with the other member for looking it against rotation so as to transmit the drive from said sun gear to the member to which the lifting connections are connected to rotate the latter member in said one direction so as to control the lowering of said part.

10. In a potato digger, frame means, a shovel unit movably connected therewith for generally vertical movement between a lowered working position and a raised transport position, a normally rotating driving gear journaled on the frame, a driven gear also journaled on said frame, linkage operatively connecting said driven gear with said shovel unit .for raising and lowering the latter, a control lever pivoted on said frame and movable into a position engaging said driven gear for holding the latter against rotation, said lever being movable into a second position to permit said driven gear to rotate, means including planetary gearing for transmitting the drive from said driving gear to said driven gear, and a cam on said driven gear engageable with said control lever for moving the latter back into said first position after a predetermined extent of rotation of said driven gear.

11. A potato digger as defined in claim 10, further characterized by depth adjusting means reacting against said frame means for adjusting the operating position of said shovel unit independently of said driven gear when the latter is held against rotation by said lever, and said linkage including lost motion means accommodating movement of said shovel unit by said depth adjusting means.

12. An agricultural implement comprising a pair of frame units one movable relative to the other, tool means movably connected with each of said frame units, a part mounted on and reacting against each frame unit for shifting the associated tool means relative thereto, power lift mechanism carried by one of said frame units, and connections arranged to accommodate relative movement between said frame units and extending from said power lift mechanism to the tool operating part of each of said units for controlling both of them.

13. An agricultural machine comprising a pair of frame units disposed alongside one another, supporting means for said frame units and accommodating both lateral adjustment of one frame unit with respect to the other and relative vertical swinging movement of one with re.- spect to the other about an axis, tool means movably connected with each of said frame units, power lift mechanism carried by one of said frame units, an operating connection extending between said power lift mechanism and the movable tool means of said one unit, and a second connection accommodating relative lateral and swinging movement between said units extending from said first connection at a point approximately adjacent said axis of relative movement to the tool means of the other unit, whereby said power lift mechanism controls both tool means.

14. An agricultural implement comprising a pair of frame units one movable relative to the other about a generally transverse axis, tool means movably connected with each of said frame units, a part mounted on and reacting against each frame unit for shifting the associated tool means relative thereto, power lift mechanism carried by one of said frame units adjacent said axis, and separate connections arranged to accommodate relative movement between said frame units and extending from said power lift mechanism to the tool operating parts, respectively, on said frame units, the disposition of said power lift mechanism adjacent said axis accommodating relative movement between said frame units without materially changing the relation between either tool means and the associated frame unit.

15. An agricultural implement comprising a pair of implement units connected together in side by side relation, each implement unit including a frame, adjustable tool means connected therewith, and means mounted on the frame for adjusting the associated tool means, a power lift mechanism supported on one of said implement units and including a rotatable part, a link connection from said part to the raising and lowering means of said one implement unit, and a link connection associated with said first mentioned link connection and extendin to the raisin and lowering means of the other implement unit whereby both of said tool means may be raised and lowered by said power lift mechanism.

16. An agricultural implement comprising a pair of implement units connected together in side by side relation for relative movement about a generally transverse axis, each implement unit including a frame, adjustable tool means connected therewith, and means mounted on the frame for adjusting the associated tool means, a power lift mechanism supported on one of said implement units and including a rotatable part, a link connection from said part to the raising and lowering means of said one implement unit, and a link connection pivotally connected with said first mentioned link connection adjacent said axis and extending to the raising and lowering means of the other implement unit whereby both of said tool means may be raised and lowered by said ed to be raised and lowered relative thereto, a

power lift mechanism on one implement, a first connection extending therefrom to the tool means of that implement, and a second connection extending from said first connection to the tool means of the other implement, whereby both tool means may be raised. and lowered by the power lift mechanism on said one implement.

18. A pair of movably interconnected agricultural implements, each having tool means adapted to be raised and lowered relative thereto, a power lift mechanism on one implement, a first connection extending therefrom to the tool means of that implement, a second connection extending from said first connection to the tool means of the other implement, whereby both tool means may be raised and lowered by the power lift mechanism on said one implement, and means for adjusting the connection between said first and second connections.

19. An agricultural implement comprising frame means, a tool unit movably connected therewith for generally vertical movement between a lowered working position and a raised transport position, a. normally rotating driving gear journaled on the frame, a driven gear also .l'ournaled on said frame, linkage operatively connecting said driven gear with said tool unit for raising and lowering the latter, a control lever pivoted on said frame and movable into a position engaging said driven gear for holding the latter against rotation, said lever being movable into a second position to permit said driven gear to rotate, means includin planetary gearing for transmitting the drive from said driving gear to said driven gear, and a cam on said driven gear engageable with said control lever for moving the latter back into said first position after a predetermined extent of rotation of said driven gear.

20. An agricultural implement comprising frame means, a tool unit movably connected therewith for movement between two positions, a normally rotating driving gear journaled on the frame, a driven gear also journaled on said frame, linkage operatively connecting said driven gear with said tool unit, a control lever pivoted on said frame and movable into a position engaging said driven gear for holding the latter against rotation, said lever being movable into a second position to permit said driven gear to rotate, means including planetary gearing and. said planetary gearing including a rotatable part which, when held against rotation, serves to transmit the drive from said driving gear to said driven gear, and means actuated by said control lever for holding said rotatable part against rotation when said control lever is moved into said second position.

21. An agricultural implement as defined in claim 20, further characterized by means actuated by the driven gear for moving the control lever back into its first position after a predetermined extent of rotation of the driven gear.

22. The combination of an agricultural implement having a part adapted to be raised into a lifted position and to return to a lowered position by gravity, power driven means operatively connectible with said part for moving it and including members movable into an approximate" 1y dead center relationship for holding said part in its lifted position, and means for optionally lowering said part through said power driven means or by gravity independently of said power driven means.

23. The combination of an agricultural implement having a part adapted to be raised into a lifted position and to return to a lowered position by gravity, power driven means connected with said part to move it into a raised position and including members movable into an approximately dead center relationship for holding said part in its lifted position, said power driven means also being releasably engageable with said part for lowering the latter at a speed determined by the rate of operation of the power driven means, said part returning to lowered position by gravity when said power driven means is in released position, and means cooperating with said power driven means and said part for optionally returning the latter to lowered position by said power means or by gravity.

24. A two-row potato digger comprising a pair of implements connected together in side by side relation, each including a generally vertically movable shovel unit, separate relatively movable frame means to which the shovel units are respectively connected, a lifting member movable on each frame means and interconnected with the associated shovel unit to move therewith, lifting mechanism mounted on the frame means of one of said implements and connected with the associated lifting member of that implement, whereby operation of said lifting mechanism acts through said lifting member to raise the shovel unit associated therewith, and a connection between said lifting mechanism on said one implement and the lifting member of the other implement whereby said lifting mechanism on said one implement controls the raising of both of said shovel units.

25. An agricultural implement comprising a. ground supported part, ground engaging tool means movable relative thereto, a support on said part, a constantly rotatable driving element mounted for rotation on said support, a driven element having a crank thereon, a link connected to said crank at the outer side thereof and with said tool means whereby rotation of said crank raises and lowers said tool means, means mount ing said driven element on said support coaxial of said driving element and in a position on said support so that the latter does not extend beyond the driven part whereby said link will clear the end of the support and said crank ma} turn through a full revolution, and controllable planetary gearing connecting said driving and driven elements.

26. An agricultural implement comprising a ground supported part, ground engaging tool means movable relative thereto, a support on said part, a constantly rotatable driving element mounted for rotation on said support, a driven element having a crank thereon, a link connected to said crank at the outer side thereof and With said tool means whereby rotation of said crank raises and lowers said tool means, means mounting said driven element on said support coaxial of said driving element and in a position on said support so that the latter does not extend beyond the driven part whereby said link will clear the end of the. support and saidcrank may turn through a full revolution, and controllable planetary gearing connecting said driving and driven elements and including a sun gear on said driving element, a ring gear member and a carrier member having planet gear means meshing with '15 said sun gear and said ring gear member, control means shiftable between two positions and carrying two sections adapted in one position to engage said driven element and in the other position to engage one of said members for driving 9 said crank or holding said crank against rotation, ptionally, and mea s for shifting said control means from one position to another.

27. The invention set forth in claim 26, further I characterized by both of said control sections be-,

ing out of engagement with said one member and said driven element in an intermediate position of said control means.

AUSTIN E. YOUNG.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,172,435 Cook Sept. 21, 1939 2,215,516 Sbhooler Sept. 24, 1940 2,059,676 Altgelt Nov. 3, 1936 2,109,667 Johnston Mar. 1, 1938 2,199,668 Lawler May 7, 1940 FOREIGN PATENTS Number Country Date 316,640 British Aug. 1, 1929 

